While this is a reasonable way to say this, and maybe effective, I think there are better points to make. Or maybe what I should say is that the single most important trait men and women of God should seek after is changeability – we’ll never find someone perfect or possibly even terribly mature; the capacity and trend to maturity are much more valuable than maturity itself.
Another way to phrase it is, learn submission.

I just get a little weirded out by the perspective of improving so you can be marriageable. I know that isn’t what you’re saying, but it kind of reminded me of it. So “becoming the person someone else will want” is more applicable when it’s “becoming submissive to and affectable by our families in Christ and Christ Himself”
… and then people will want to marry you…? I don’t know.